A structure or substance or substance not normally present but produce by some external force or action. Example : mercury pigment, tissue floater , knife lines, and air bubble.

PIGMENT

A heterogenous group or substance that contain enough natural color to be visible w/o any futher staining. Example: melanin

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HYPERTONIC

A solution that will cause cells to swell. Example: sodium chloride solution of less that 0.9% concentration are hypontonic to aninal tissue cells.

ISOTONIC

Fluid into which normal animal cells can be placed w/o causing either swelling or shrinkage.

TWO WAYS TO FIX TISSUE

Chemical ( fixative solution)

Physical ( heat and dessication)

DENATURATION

Causes the molecules to unfold and the internal bonds to become disrupted.

ADDITIVE FIXATIVE

The disruption enables the protein to combine w/ a fixative molecule, and the protein then becomes insoluble.

NON ADDITIVE FIXATIVE

Examples are alcohol and acetone. denaturation causes the protein to become less capable of maintaining an intimate relationship with water and to become more reactive - fixative molecules does not combine with the protein.

DEFINE PUTREFACTION

Bacterial attack

DEFINE AUTOLYSIS

Enzyme attack

FIXATIVE FUNCTION AND ACTIONS

Kill tissue

Help maintain the proper relationship between cell and extracellular substances such connective tissue fibers and amorphous ground substances.

Bring out refractive index

enhance staining

render cell constituents insolunle

harden tissue

penetrate

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DEFINE COAGULANT

Establish a network that allows solutions to penetrate or gain entry into the interior of the tissue. ---like a mesh ball

DEFINE NON COAGULANT

Does not allow good penetration by the reagents. like a gel.

FACTORS INFLUENCING FIXATION

Temp

Size

Volume ratio

Time

Choice of Fixative

Penetration

PH

Osmolality

DEFINE POST FIXATION OR MORDATING

A reagent used to link the stain to dye molecule to the tissue.

What fixative demostrate chromaffin granules?

Primary Dichromate

Ortho solution

What fixative demostrate urate crystals

Absolute alcohol

What special stain use bounin a mordate?

Trichome

What fixative is used for optimal demostration of muscle cross striation when being stained with PTAH?

Zenker

What are the preferred fixative for nucleic acids?

Acetic Acid and Carnoy Solution

What two chemical fixative will fix lipids?

Osmium tetroxide and Chromic Acid

FIXATIVE

It alter the tissue by stablizing the protein so that it resistant to futher change. Fixative change the soluble content of the cell into insoluble substances to prevent the lost subsequent processing steps.

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